package tech.yangzhijie.basic.demo02.util;

import sun.misc.BASE64Decoder;
import sun.misc.BASE64Encoder;

import javax.crypto.*;
import javax.crypto.spec.SecretKeySpec;
import java.io.IOException;
import java.io.UnsupportedEncodingException;
import java.security.InvalidKeyException;
import java.security.NoSuchAlgorithmException;
import java.security.SecureRandom;

public class AESUtils {

    /*
     * 加密
     * 1.构造密钥生成器
     * 2.根据ecnodeRules规则初始化密钥生成器
     * 3.产生密钥
     * 4.创建和初始化密码器
     * 5.内容加密
     * 6.返回字符串
     */
    public static String AESEncode(String encodeRules,String content){
        try {
            Cipher cipher = getCipher(encodeRules, Cipher.ENCRYPT_MODE);
            //8.获取加密内容的字节数组(这里要设置为utf-8)不然内容中如果有中文和英文混合中文就会解密为乱码
            byte [] byte_encode=content.getBytes("utf-8");
            //9.根据密码器的初始化方式--加密：将数据加密
            byte [] byte_AES=cipher.doFinal(byte_encode);
            //10.将加密后的数据转换为字符串
            //这里用Base64Encoder中会找不到包
            //解决办法：
            //在项目的Build path中先移除JRE System Library，再添加库JRE System Library，重新编译后就一切正常了。
            String AES_encode=new BASE64Encoder().encode(byte_AES);
            //11.将字符串返回
            return AES_encode;
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        } catch (UnsupportedEncodingException e) {
            e.printStackTrace();
        }

        //如果有错就返加nulll
        return null;
    }
    /*
     * 解密
     * 解密过程：
     * 1.同加密1-4步
     * 2.将加密后的字符串反纺成byte[]数组
     * 3.将加密内容解密
     */
    public static String AESDecode(String encodeRules, String content){
        try {
            Cipher cipher = getCipher(encodeRules, Cipher.DECRYPT_MODE);
            //8.将加密并编码后的内容解码成字节数组
            byte [] byte_content= new BASE64Decoder().decodeBuffer(content);
            /*
             * 解密
             */
            byte [] byte_decode=cipher.doFinal(byte_content);
            String AES_decode=new String(byte_decode,"utf-8");
            return AES_decode;
        } catch (NoSuchAlgorithmException e) {
            e.printStackTrace();
        } catch (NoSuchPaddingException e) {
            e.printStackTrace();
        } catch (InvalidKeyException e) {
            e.printStackTrace();
        } catch (IOException e) {
            e.printStackTrace();
        } catch (IllegalBlockSizeException e) {
            e.printStackTrace();
        } catch (BadPaddingException e) {
            e.printStackTrace();
        }
        return null;
    }

    private static Cipher getCipher(String encodeRules,int mode) throws NoSuchAlgorithmException, NoSuchPaddingException, InvalidKeyException {
        //1.构造密钥生成器，指定为AES算法,不区分大小写
        KeyGenerator keygen=KeyGenerator.getInstance("AES");
        //2.根据ecnodeRules规则初始化密钥生成器
        //生成一个128位的随机源,根据传入的字节数组
        keygen.init(128, new SecureRandom(encodeRules.getBytes()));
        //3.产生原始对称密钥
        SecretKey original_key=keygen.generateKey();
        //4.获得原始对称密钥的字节数组
        byte [] raw=original_key.getEncoded();
        //5.根据字节数组生成AES密钥
        SecretKey key=new SecretKeySpec(raw, "AES");
        //6.根据指定算法AES自成密码器
        Cipher cipher=Cipher.getInstance("AES");
        //7.初始化密码器，第一个参数为加密(Encrypt_mode)或者解密(Decrypt_mode)操作，第二个参数为使用的KEY
        cipher.init(mode, key);
        return cipher;
    }

    public static void main(String[] args) {
        //Scanner scanner=new Scanner(System.in);
        /*
         * 加密
         */
        /*System.out.println("使用AES对称加密，请输入加密的规则");
        String encodeRules=scanner.next();
        System.out.println("请输入要加密的内容:");
        String content = scanner.next();
        System.out.println("根据输入的规则"+encodeRules+"加密后的密文是:"+AESUtils.AESEncode(encodeRules, content));*/

        /*
         * 解密
         */
        /*System.out.println("使用AES对称解密，请输入加密的规则：(须与加密相同)");
        encodeRules=scanner.next();
        System.out.println("请输入要解密的内容（密文）:");
        content = scanner.next();
        System.out.println("根据输入的规则"+encodeRules+"解密后的明文是:"+AESUtils.AESDecode(encodeRules, content));*/

        String encodeRules = "pBGnFDKB4RXTIxlAADJcIrY2";
        String content = "{\"random\":\"73824\",\"param\":\"K7jQF0dbRJmbyCa4h9xc2ZLaEbisUwn1V6fOjnBdXTg=\",\"appId\":\"HRZR\",\"sign\":\"e20cd5c93132481556a3b9d6316858d4\",\"type\":\"1\",\"timestamp\":\"20190325171626\"}";
        String encode = AESUtils.AESEncode(encodeRules, content);
        System.out.println("encode: "+encode.length());
        String decode = AESUtils.AESDecode(encodeRules, encode);
        System.out.println("decode："+decode);
    }
}
